One residual clinical feature of chronic aphasics is a speech output disorder. Nonfluent aphasics have limited speech output and articulatory implementation deficits in which the sounds of language produced are often distorted and hard to understand by listeners. Some fluent aphasics select the wrong sounds comprising a word, making successive attempts impacting the aphasic's willingness to speak. The goal of the current project is to apply basic research to the development and preliminary testing of a novel rehabilitation program, 'Therapy Program to Improve Phonetic Production' (TIPP), designed to improve the quality of the acoustic- phonetic output and ultimately the speech intelligibility of aphasic participants. TIPP builds off of basic research on the functional architecture of spoken word production in normals showing that articulatory implementation is influenced by the lexical properties of the stimulus; fMRI results showing the neural system recruited in such processing; and recent findings indicating spared properties of the functional architecture of spoken word production in aphasia. Five nonfluent aphasics who have speech output deficits, and five fluent aphasics who produce phonemic paraphasias, will participate. It is hypothesized that exposure to and modeling speech under different speaking conditions can shape and strengthen the lexical and sound shape representations of words; training with minimal pair words (tart vs. dart) will enhance the distinction between similar sounding words leading to strengthening phonetic and phonological representations and improved quality of the phonetic output; this strengthening will generalize to untrained words that share voicing with the trained words and will also have a cascading effect on accessing lexical representations leading to increased naming ability and spoken output fluency. TIPP is a 10 week, 2-session per week, protocol which includes a two part training phase, one in which the participant is trained to produce a set of alveolar stop consonant minimal pair target words embedded in a carrier phrase spoken with normal intonation but at a slowed pace, and the other in which the participant is trained to intone the same set of target words embedded in the carrier phrase, also at a slowed pace. To assess the program, acoustic analyses will be conducted to determine whether there is a greater distinction between voiced and voiceless stop consonants post-training, whether there are changes in the number of tokens successfully produced, the number of sound errors made, and the number of false starts or stutters, and where there are changes in intelligibility. Generalization and maintenance 2 and 6 monthspost- therapy will be assessed on a set of untrained labial and velar word tokens and on other language variables including naming and speech fluency. The number of adults who have a residual aphasia after a neurological event is in the millions, and the effects on their lives as well as their families are devastating. This research holds promise of establishing a new protocol to improve the quality and intelligibility of the speech output of aphasic participants leading to a substantive improvement in their communication abilities.